An autonomous travel device that travels autonomously by driving wheels has been developed. For example, the autonomous travel device can be used in a case of monitoring an obstacle on a monitoring route (a patrol pathway), or the like. In this case, the autonomous travel device travels autonomously on a monitoring route at a set speed, which is set in advance.
Such an autonomous travel device includes wheels, a device main body, a power source, and a battery. The battery supplies power to a power source. The power source causes the device main body to travel autonomously by driving the wheels using power of the battery.
In a case in which an electric motor, or the like, is used as a power source, a large-capacity battery is necessary in the autonomous travel device. However, a large-capacity battery takes a lot of time to charge. Therefore, a method for replacing the entire battery is used. In this manner, in an autonomous travel device, it is desirable to make replacement of the battery easy in order to allow replacement of the battery to be performed rapidly.
In addition, if the capacity of the battery is increased in the manner of a large-capacity battery, the weight of the battery is also increased. A power source is also a heavy mechanism unit, but the weight of the battery is the heaviest among the members of the autonomous travel device. That is, the center of gravity of the autonomous travel device (the device main body) changes greatly depending on the disposition of the battery. Therefore, in the autonomous travel device, it is desirable to dispose the battery in consideration of the center of gravity of the device main body in order to allow stabilized autonomous travelling.
PTL 1 discloses a vehicle (an electric vehicle) equipped with a battery. In the technique disclosed in PTL 1, a battery replacement device for replacing a battery is provided below a vehicle body and allows replacement of the battery from below the vehicle body. The battery replacement device is provided below a ground contact surface of wheels between left and right wheels. In the technique disclosed in PTL 1, it is possible to easily perform replacement of the battery by using the battery replacement device.
PTL 2 discloses a vehicle (a passenger vehicle) equipped with a battery. In the technique disclosed in PTL 2, a partition is provided in a supplementary unit chamber, which is provided in a vehicle body, and a battery is disposed therein. In the technique disclosed in PTL 2, it is possible to easily perform replacement of the battery by using the partition.